DO NOW: 1.What is energy? 2.What requires energy? 3.How do cells obtain energy?

Energy is defined as the ability to do work There are two main forms of energy –Potential and Kinetic

Energy and Thermodynamics Two main categories of energy Stored energy is called Potential energy Energy has the “potential” to do work if released Motion energy is called Kinetic energy Energy which is being released and actively doing work

Energy and Thermodynamics Energy has many forms –Chemical (glucose, ATP) –Thermal (heat) –Radiant (sun)

Energy and Thermodynamics Energy is NOT created or destroyed, it can only be changed from one form to another Conservation-Of-Energy BUT energy does “flow” to a point where the energy is converted to an unusable form (heat) Light  Glucose  ATP  Heat

How is Matter “Changed” or rearranged in living things? Metabolism ALL the biochemical reactions in cells used to obtain OR use energy (both building and breaking) Breaking down food Building bone and muscle Growing Repair (healing) Cleanup (from an infection)

ANABOLISM - building Plants can take CO2 and H2O and turn them into glucose. All organisms can make proteins from amino acids Joining small things together to make bigger things is called ANABOLISM. Metabolic reactions that use energy Energy is used to do this

Catabolism – breaking down Animals often need to breakdown matter into smaller parts in order to absorb the matter into their cells. Plants (and embryos) need to break down stored starch and lipids for energy Enzymes breakdown dead/decaying material. This is called CATABOLISM Metabolic pathways which break down

Ultimate Source of Energy Matter is changed many times Fusion happens in the sun H  He  other elements Released energy (Electromagnetic energy (radiation) Plants convert EM energy to chemical energy (glucose)

What is ATP (Adenosine Tri-Phosphate)? The only molecule cells can use to do work in living things: Adenine Ribose 3 Phosphate groups Basically a Nucleotide with two extra phosphates!

What’s the deal with ATP? Energy molecule for life Hydrolyzing (breaking off) third phosphate frees energy which can be used to do work in the cell ADP (what is left) can be recycled.

What’s the deal with ATP To recycle ADP back to ATP, the cell uses energy from glucose to add a 3 rd phosphate ATP is made again

ADP and ATP

ADP/ATP cycle

Electron Carriers Molecules that “pick up” high energy electrons and carry them until their energy is needed elsewhere. Examples : NADH (CR); FADH 2 (CR) NADPH

NADH FADH2 NAD+ FAD e-e- to charge ATP from glucose e-e-

NADPH NADP+ e-e- to make glucose From sun e-e-

ENERGY FLOW AND LIFE

Electromagnetic Spectrum Energy can travel in vibrations or waves. Different types of energy have a different number of vibrations per period of time. This is called frequency. Scientists organize waves according to their frequency or wavelength in the electromagnetic spectrum.

Light Energy Sunlight sometimes called white light, is a form of energy that we can see and it travels in waves. Wavelength: the distance between the crest of one wave and the crest of the next wave

Visible Light Spectrum Depends on wavelength Blue: 380 (nm) Green: 500 (nm) Yellow 560 (nm) Light red: 600 (nm) Darker red: 750 (nm)

1600s: Jan van Helmont Grew a small willow tree and only added water to the plant. After five years the tree gained 75 kg, but the soil had the same mass. Where did the new plant material come from?

1770s: Joseph Priestley Placed a plant in a closed container with a candle. –“damaged air” Candle will go out and animals cannot live under these conditions. Plants can live and restore the ability of the air to support a flame and an animal. How do plants interact with air?

A few years later… Antoine Lavoisier –Oxygen removed from air during burning Animals need oxygen to survive. What about plants?

Other discoveries in the 1700s… Jan Ingenhousz –Plants only give off oxygen in sunlight Jean Senebier –Plants take in carbon dioxide during growth in sunlight

1800: Requirements for Plant Growth Determined Carbon dioxide Water Light

Plant Nutrition

Photosynthesis Process of capturing energy of sunlight and transforming it into chemical energy

Equation for Photosynthesis Light + CO 2 + H 2 O--glucose + O 2

Autotrophs Organisms that are capable of making food from simple inorganic substances EX: green plants, algae

Two Types of Autotrophs 1. Photoautotrophs: use carbon dioxide and light energy to drive reactions needed to make food 2. Chemoautotrophs: utilize inorganic chemicals for the energy to drive food making reactions

Heterotrophs Organisms that cannot make their own food and must depend on other plants or animals as food source Examples: ___________

PIGMENTS Pigments: absorb light EX: a red object absorbs all the visible colors of the spectrum except red which is reflected and gives the object the red color

CHLOROPLAST Organelle that contains photosynthetic pigments that absorb light energy

Types of Photosynthetic Pigments a.Chlorophyll: appear green  absorbs red and blue light b.Carotenes: appear orange c.Xanthophylls: appear yellow

CHLOROPLAST Site of Photosynthesis Found in what type of cells?

Parts of the chloroplats: THYLAKOID contains photosynthetic pigments; flattened membrane sacs

Grana Stacks of thylakoids

Stroma Fluid region between grana –Contains DNA, ribosome, starch grains Why do chloroplasts have their own DNA?